单项选择题
When youre performing active database duplication，a backup of what kind is required？（）
A. A current RMAN backup-set backup is required. B. No backup is required. C. An RMAN image backup is required. D. A manual backup is required. E. A "duplicate" preparatory backup is required.
单项选择题 Whichcommandisusedtobeginatablespacepoint-in-timerecovery？（）
单项选择题 tablespacepoint-in-timerecoveryispossibleonlywithRMAN.（）
单项选择题 Ifabackupisexpired，whichofthefollowingistrue？（）
